# Biot-Savarts law

1. Feb 11, 2012

### Niles

Hi

When solving Biot-Savarts law for a current loop of radius R, the magnetic field on the axis of the loop is given by (in Tesla)
$$B(z) = \mu_0I\frac{R^2}{(R^2+z^2)^{\frac{3}{2}}}$$
where I is the current through the loop. However, this derivation assumes that the loop has an infinitesimal thickness. But how is the "proper" way to take into account the fact that a current loops has a finite thickness?

My book on Electrodynamics (Griffiths) does not address this issue, and it is something I have thought about for some time.

Best,
Niles.

2. Feb 11, 2012